Exploitation of Heterosis and Combining ability for Yield and its Contributing traits in Crosses of Two-row and Six-row barley (Hordeum vulgareL.) under Rainfed Environment.

Abstract

Combining ability for grain yield and its components in barley was studied in a set of four females (Testers 6 rowed), six males (lines 2 rowed) and their resultant F1’s with standard check k-603. Twenty two crosses, excluding BCU -4925 x K-603 and BCU-4922 x Karan-16, showed significant positive economic heterosis for grain yield per plant. Analysis for variance for combining ability analysis revealed that the variance due to General Combining Ability (GCA) and Specific Combing Ability (SCA) were highly significant for most of the traits studied. The estimated value of σ2A was higher than its σ2D for plant height and thousand seed weight which indicated the predominance of additive gene action as the ratio of σ2A/σ2D was more than unity, while rest of the traits showed preponderance of non-additive gene action. The value of average degree of dominance for plant height and thousand seed weight indicated partial dominance while rest of the traits viz., chlorophyll content, spike length, awn length, number of effective tillers, number of grains per spike, harvest index and grain yield per plant showed over-dominance. Two male parents (BCU-4925 and BCU-4927) and one male parent (Lakhan) had significant and positive effect for grain yield per plant. Five crosses were found to be good specific combiners for grain yield with maximum SCA effect in cross BCU-4922 x Lakhan.